Door closer



Jan 1951 M. KALTHOFF 2,537,059

DOOR CLOSER Filed D80. 22, 1948 2 Sheets-Sheet 2 FIG. 8

AT TORNEYS Patented Jan. 9, 1951 UNITED STATES PATENT OFFICE DOOR CLOSER Max Kalthofr", Glenbrook, Conn.

Application December 22, 1948, Serial No. 66,749

13 Claims. 1

This invention relates to door closers of the type in which a spring is employed for closing the door and the closing action is regulated by forcing liquid through an orifice, which may be adjusted in size. More particularly, the invention is concerned with a novel door closer, which is of simple construction and may be adapted for use on either a right-hand or a left-hand door by a simple adjustment of parts, which can be made without taking the closer apart. The new closer offers a further advantage over prior similar closers, in that a door equipped with a closer can be pushed shut quickly without placing any substantial strain on the closer mechanism. The new close-r includes a cylinder containing .a piston having an extension which is internally threaded and is provided with a pair of external diametrical projections. The piston is moved outwardly with reference to the cylinder by the rotation of one or the other of a pair of concentric shafts, one of which has a threaded section screwed into the piston extension and the other of which has slots receiving the projections. The shafts are .acted on by spring means tending to rotate them in opposite directions, and the operating arm of the closer, which is pivoted to swing on the axis of the shafts, may be connected optionally to either shaft. The rotational movement .of the shafts is limited by stop means and, when the operating arm is moved in one direction, it rotates one of the Shafts and winds up the spring, which then acts to hold the second shaft at .the limit of its movement determined by the stop means. The movement of the first shaft causes the piston to move outwardly relative to the cylinder and liquid is drawn into the cylinder beneath the piston. When the operating arm is released, the spring unwinds, causing reverse rotation of the first shaft and inward move- .ment of the piston, which forces liquid from the cylinder through an outlet orifice. If, when the arm is being restored to its initial position by the action of the spring, additional restoring force is applied to the arm, the result is that the second shaft is rotated in a direction away from the stop means and, during such movement, the inward movement of the piston is arrested. Thereafter, when the arm has returned to its initial position, the further unwinding of the spring causes the second shaft to return to the limit of its movement and the piston continues in Accordingly, the ap-" wardly into the cylinder. plication of additional restoring force to the operating arm does not cause an increased force .tobe applied to the piston and damage to the mechanism of the closer is prevented.

For a better understanding of the invention, reference may be had to the accompanying drawing, in which Fig. 1 is a sectional View through one form of the door closer of the invention, on the line -i-! of Fig. 5, the operating arm being broken away;

Fig. 2 is a partial sectional view at an angle to Fig. 1;

Figs. 3 and 4 are sectional views on the lines 3-3 and di, respectively of Fig. 1;

Fig. 5 is a top plan view of the closer showing it installed on a right-hand door;

Fig. 6 is a top plan view of the closer with the operating arm removed;

Fig. 7 is a view similar to Fig. 6 with parts broken away; and

Fig. 8 is a view similar to Fig. 5 showing the closer installed on. a left-hand door.

mounted inside the chamber on the bottom thereof and is centrally bored to receive a ball bearing 12. A partition H of cup form is secured on top of the block, the partition defining a cylinder open at the top. A projection M extending downwardly from the lower end of the cylinder at one side of block ii is formed with an inlet passage 15 containing a ball 15 acting as a check valve, the ball being held in place by a pin I! mounted in an opening through the partition and extending into the passage above the ball. Near its closed end, the side wall of the cylinder is formed with an outlet opening it, into which projects the end of a rod is. The rod extends through a hollow boss 2!! on the side Wall of chamber ID and has a threaded section lea screwed into internal threads within the boss. Leakage from the chamher along the rod is prevented by packing 2i lying Within the boss in contact with the rod and held in place by a packing nut 22 threaded into the end of the boss. The outer end of rod 19 carries a knurled disc 23, by which the rod maybe turned in or out. The position of the inner end of the rod is in outlet opening 98 determines the rate of flow through the opening.

.A piston 2 is disposed within the cylinder and its upper face has a cylindrical extension Me, which is internally threaded and, preferably, with .a multiple thread. The piston extension is also provided with .a pair of external .diame'trical pro- ;iections, preferably, taking the form of rollers 25 mounted on ball bearing on studs 26 threaded into openings in the extension.

The top of the chamber It is closed by a cover nut 42. outer shaft exposed above the bearing tube is 21 threaded into the end of the chamber and provided with a bracket 28, by which the closer can be attached to a door, and with a central tubular bearing tube 29 extending upwardly therefrom. An outer shaft 30 is mounted for rotation within the bearing tube and the shaft pro- J'ects through the cover and carries a cylindrical extension 31 at its lower end, provided with longitudinal slots 32, within which rollers 25 on the piston extension are received. An inner shaft 33 extends through the outer shaft 30 in contact therewith and through the piston extension, the bottom of the piston, and into the inner race of ball bearing l2. Shaft 33 is formed with a threaded section 34, which is screwed into the internal threads within the piston extension 24a.

A lower spring cup 35 is mounted on top of cover 21, the cup being formed with an inner tubular wall 36 in contact with the outer surface of bearing tube 29. Above cup 35 is mounted an upper spring cup 31, which has an inner tubular wall 38 surrounding and in contact with the bearing tube 29. The cups are concave to one another and together define a cavity. The bore of bearing tube 29 is enlarged at the upper end of the tube and contains packing 39 held in place against the outer surface of shaft 30 by a nut 43 threaded into the tube bore. I

The upper end of the outer shaft 30 projects above the upper end of the bearing tube 29 and is internally bored to receive packing 4| held against the surface of inner shaft 33 by a packing The outer surface of the portion of the formed with one or more flats. A radial arm 43 is mounted on and secured to the upper end of the upper spring cup 31 by screws 43a and the arm encircles the upper end of the outer shaft beyond the upper end of the outer shaft and into the hub 44 of a radial arm 45, which has an end portion 45a extending downwardly past the up- 29 is counterbored at 55 and the radial wall of extension 3| on the outer shaft 39 is formed with openings 56, through which oil from the chamber may pass to lubricate the outer shaft within the bearing tube. The lower end of the outer shaft is also counterbored at 51 to permit oil to enter the outer shaft and lubricate the inner shaft.

When the new closer is installed on a door, the long end of its operating arm 41 is connected in the usual way by a link to the door frame. If the door is of the right-hand type, as shown in Fig. 5, the short end of the operating arm is connected to arm 43 by inserting bolt 50 in hole 43b in the arm, so that, when the door is opened, the arm is swung counter-clockwise, when the closer is viewed from the top, and the upper spring cup 31 and the outer shaft are rotated in the same direction. As a result, the springs are wound up and they react against the bottom spring cup to hold it with its lug 53 in tight contact with the stop lug 52 on bracket 28. In the movement of the outer shaft 30, the walls of the slots 32 in the shaft extension 3! act on rollers 25 on the piston extension and cause the piston to move helically upward along the multiple thread on section 34 of the inner shaft, which is stationary. As the piston rises, liquid from the chamber is drawn and. is fast thereon. The inner shaft 33 projects I per spring cup 31 and secured to the outer wall of 1 the lower spring cup 35 by a screw 43. The upper end of the inner shaft 33 is formed with a flat and i the bore of the hub is correspondingly formed, so

7 that arm is fast on the shaft. An operating arm 41 is mounted to swing about the axis of the shafts and, in the construction shown, the arm has an opening through which hub 44 extends.

The arm is held in place by means of a washer 48 and a nut 49 screwed on the threaded end section 33a of the inner shaft 33. The short end of the operating arm is provided with an opening to receive a bolt 50, which may be threaded into a threaded hole 431) in arm 43 connected to the outer shaft or into a threaded hole 451) in arm 45 connected to the inner shaft.

The cavity defined by spring cups 35 and 31 contains spring means illustrated as made up of inner and outer coil springs 5!. The upper end of each spring is received in a recess in the top wall of the upper spring cup 31 and the lower end of each spring is received in an opening in the bottom wall of lower spring cup 35. The bracket 28 attached to the cover is provided with a stop lug 52 and the cups 35 and 31 are provided with lugs 53, 54, respectively, on their cylindrical surfaces in position to engage lug 52. The springs tend to rotate cups 35 and 31 in opposite directions and, under normal conditions, the springs rotate the cups, until the cup lugs 53, 54 engage the stop lug 52 from opposite sides.

The chamber I0 is filled with oil, when the into the cylinder through the inlet check valve. When the door is released, the springs tend to unwind and this causes the upper spring cup, arm 43, and the outer shaft 33 to rotate clockwise. In such movement, the walls of the slots 32 act on rollers 25 and move the piston downwardly on the threaded section 34 of the inner shaft 33. As the piston moves downwardly, it forces oil from the cylinder into the chamber through the outlet, and the rate of downward movement of the piston and, accordingly, the rate at which the door closes, depend on the size of the outlet orifice as determined by the position of rod IS in opening l8. The outlet orifice is a short distance above the closed end of the cylinder and the inner surface of the cylinder has a short slot 58, leading downward to the top of the opening I 8. When the piston reaches the slot, the door will be nearly closed and, as soon as the edge of the piston has passed below the upper end of the slot, liquid can flow around the edge of the piston, so that the latter may be more quickly closed by the springs and the last few degrees of closing movement of the door are at a more rapid rate. This insures that the door will have sufficient momentum to move back the latch of the door lock.

When the closer is insta led on a left-hand door, the operating arm 41 is connected to the arm 45 attached to the lower spring cup by inserting bolt 59 into hole 45!; in the arm. When the door is opened, the operating arm is swung clockwise, when the closer is viewed from the top, and this causes clockwise rotation of the lower spring cup and of the inner shaft 33. As the shaft thus rotates, its threaded section is screwed into the internal threads in the piston extension and, since the outer shaft 33 is stationary, the piston cannot rotate and merely rises vertically with its rollers 25 traveling through slots 32. When the door is released, the springs unwind and cause counter-clockwise rotation of the inner shaft and downward movement of the piston in the cylinder.

If the closer is installed on a door, for example one of the left-hand type, and the door is opened and then pushed closed, the following action takes place. In the opening of the door, the

closer is in use, and the lower end of bearing tube operating arm 41. the l wer pr g 11 35, and

the inner sh'aft are moved -c1o'ckwise to raise the piston and, at the same time, the reaction of "the springs on the upper spring cap 31 causes the lug 56 thereof to press tightly against the stop lu'g When the door is released, the 'springs senate swing'th'e lower spring cop and the inner shaft counterclockwise, so that th'erpiston moves downwards intothe cylinder. If, at this time, additibnal force is applied to the door, the resistance to fio'w froin the cylinder through the outlet into the fcha'inbe-r prevents the piston from being moved dow nwar-dly more rapidly. The additional closing fo'r-ce theh causes the rollers 25 on the piston extension'to act on the walls "of slots 32 in the extension on the outer shaft and cause that shaft to rotate coa-nter cloclrwise. Such rotation of the "outer shaft causes the upper spring cup -31 to rotate counter-clockwise, so that its ill-g '54 ihdv'es away from step 52. When the door is closed, the am t! "will have reached a position, in which the lower spring cup lies with its lug 53 against stop lug 52. The springs now unit/ind and cause a "clockwise movement of the upper spring cup and the outer shaft, until lug '54 on the upper cup engages the stop log 52. During such movement of the upper spring clip and cater-shaft, the piston isrotated by the action of the wals of slots 32 on rollers 25 and the piston motes helio'ally downward along the threaded section 3 1 of the inner shaft, until it reaches the lower en'do f the cylinder. Thus, the application of additional closing force to -the door does not place anyundue strain upon the mechanism, since during the application of the force, the downward movement of the piston is arrested and, thereafter, when the door is closed, it moves to its tower-most position by spring action.

'1. In a door closer, the combination of a cylinder having a closed end, an inlet into and an 1:,

outlet from the cylinder adjacent its closed end, the inlet containing an inlet check valve and the outlet containing a control Valve, a piston within the cylinder having an internally threaded axial extension provided with-caramel diametrical projections, a pair of 'cb-ncentric rotatable shafts, the inner shaft-having-a threaded section screwed into the pistonextension and the outer shaft having longitudinal slots receiving the projections on the piston extension, stop means, members connested to the respective shafts to rotate therewith and engageable with the stop means to limit retatio-n of thesha fts, spring means connected to the shafts and urging them to rotate in opposite directions and hold the members in engagement with the stop means, an operating arm pivoted to swing on the axis of the shafts, and means for "connecting the arm to one of the shafts.

2. In a door closer, the combination of a'cylin- (for having a closed end, an inlet into and an outlet from the cylinder adjacent its closed e'nd, the inlet containing an inlet check valve and the outlet containing a c'ontrolvalv'e, a piston within the cylinder having an internally threaded axial extension provided with external diametrlcal projections, a pair of concentric rotatable shafts, the inner shaft having a threaded section screwed into the piston extension and the outer shaft havi'ng longitudinal slots receiving the projections on the piston extension, a mounting for the shafts, stop means on the mounting, members connected to the respective shafts to rotate therewith ahd engageable with the stop means to *li mit rotation of the shafts, spring means con- T-f'e'cted to theshaifts and 'nrgin'g them to rbtate in 6 opposite directions and hold the members in engagement with the stop means, an operating farm pivoted to swing on the axis of the shafts, and means for connecting the arm to one of the shafts.

3. a door closer, the combination of a cylinder having a closed end, an inlet into and an outlet from the cylinder adjacent its closed end, the inlet containing an inlet check valve and the outlet containing a control valve, 2. piston with-in the cylinder having an internally threaded axial extension provided with external diametrical projections, a pair of concentric rotatable shafts, the inner shaft having a threaded section screwed into the piston extension and the outer'shaft having longitudinal slots receiving the projections on the piston extension, a pair of members connected to the respective shafts to rotate therewith, the members together defining a cavity, stop means engageable by the members to limit the rotation of the shafts, spring means within said cavity connected to the members and urging them to rotate with their shafts in opposite directions and hold the members in engagement with the stop means, an operating arm pivoted to swing on the axis of the shafts, and means for connecting the arm to one of the shafts. V 4. In a door closer, the combination of a cylinder having a closed end, an inlet into and an outlet from the cylinder adjacent its closed end, the inlet containing an inlet check valve and the outlet containing a control valve, a piston within the cylinder having an internally threaded axial extension provided with external diametrical r011- ers, a pair of concentric rotatable shafts, the inner shaft having a threaded section screwed into the piston extension and the outer shaft havin longitudinal slots receiving the rollers on the piston extension, stop means, members connected to the respective shafts to rotate therewith and engageable with the stop means to limit rotation of the shafts, spring means connected to the shafts and urging them to rotate in opposite directions and hold the members in engagement with the stop means, an operating arm pivoted to swing on the axis of the shafts, and means for connecting the arm to one 'of the shafts.

5. In a door closer, the combination of a cylinder having a closed end, an inlet into and an outlet from the cylinder adjacent its closed end, the inlet containing an inlet check valve and the outlet containing a control valve, a piston within the cylinder having an internally threaded axial extension provided with external diametrical projections, a pair of concentric rotatable shafts, the inner shaft havin a threaded section screwed into the piston extension and the outer shaft having longitudinal slots receiving the projections on the piston extension, stop means, upper and lower members through which the shafts ex tend, the upper member being connected to the outer shaft and the lower member being connected to the inner shaft, the members rotating with their respective shafts and being engageable with the stop means to limit rotation of their shafts, spring means connected to the members and ur in them to rotate in opposite directions and hold the members in engagement with the stop mean an operating arm pivoted to swing on the axis of the shafts, and means for connecting the arm to one of the shafts.

6. in a door closer, the combination of a chamb r. a partit on within the chamber defining a cylind r he ving a closed end, connections between the cvlinder adjacent its clo ed end and the chamber, one connection containing an inlet check valve and the other an outlet control valve, 9, piston within the cylinder having an internally threaded extension provided with diametrical projections from its outer surface, an inner shaft having a threaded section screwed into the piston extension, an outer shaft surrounding the inner shaft, and provided with longitudinal slots receiving the projections on the piston extension, upper and lower spring cups encircling the shafts above the chamber and rotatable about the axis thereof, stop means limiting the rotation of the cups, spring means within the cups urging them in opposite directions against the stop means, a connection between the upper cup and the outer shaft, a connection between the lower cup and the inner shaft, an operating arm pivoted to swing about the axis of the shafts, and means for connecting the arm to one of the cups.

7. In a door closer, the combination of a chamber, a partition within the chamber defining a cylinder having a closed end, connections between the cylinder adjacent its closed end and the chamber, one connection containing an inlet check valve and the other an outlet control valve, a piston within the cylinder having an internally threaded extension provided with diametrical projections from its outer surface, a pair of concentric rotatable shafts projecting out of the chamber, the inner shaft having a threaded section screwed into the piston extension and the outer shaft having longitudinal slots receiving the projections on the piston extension, a mounting outside the chamber for the shafts, stop means on the mounting, members connected to the respective shafts outside the chamber for rotation with the shafts and engageable with the stop means to limit rotation of the shafts, spring means connected to the shafts and urging them to rotate in opposite directions and hold the members in engagement with the stop means, an operating arm pivoted to swing on the axis of the shafts, and means for connecting the arm to one of the shafts.

8. In a door closer, the combination of a chamber, a partition within the chamber defining a cylinder having a closed end, connections between the cvlinder adjacent its closed end and the chamber, one conne tion cont ining an inlet check valve and the other an outlet control valve, a piston within the cylinder having an internally threaded extension provided with diametrical projections from its outer surface, a pair of concentric rotatable shafts projecting out of the chamber, the inner shaft having a threaded section screwed into the piston extension and the outer shaft having lon itudinal slots receiving the projections on the piston extension, a cover for the chamber provided with a mount ng for the portions of the shafts outside the chamber, stop means on the cover, members connected to the respective shafts outside the chamber for rotation with the shafts and engageable with the stop means to limit rotation of the shafts, spring means acting on the m mbers and urging them to rotate in opposite directions and hold the mem ers in engagement with the stop means, an operating arm pivoted to swing on the axis of the shafts, and means for connecting the arm to on of the shafts.

9. In a door closer. the combinat on of a chamher, a partition within the chamber defining a cylinder having a closed end, connections between the cylinder adjacent its closed end and the chamber, one connection containing an inlet the projections on the piston extension, a cover for the chamber provided with means for attaching the closer to a door and a bearing for the portion of the outer shaft outside the chamber, stop means on the cover, members connected to the respective shafts outside the chamber for rotation with the shafts and engageable with the stop means to limit rotation of the shafts, spring means acting on the members and urging them to rotate in opposite directions and hold the members in engagement with the stop means, an operating arm pivoted to swing on the axis of the shafts, and means for connecting the arm to one of the shafts.

10. In a door closer, the combination of a chamber, a partition within the chamber defining a cylinder having a closed end, connections between the cylinder adjacent its closed end and the chamber, one connection containing an inlet check valve and the other an outlet control valve, a piston within the cylinder having an internally threaded extension provided with diametrical projections from its outer surface, a pair of concentric rotatable shafts projecting out of the chamber, the inner shaft having a threaded section screwed into the piston extension and the outer shaft having longitudinal slots receiving the projections on the piston extension, a cover for the chamber provided with means for attaching the closer to a door and a bearing for the portion of the outer shaft outside the chamber, a pair of cup members mounted on the outside of said bearing and together defining a cavity, arms fast on the respective shafts and connected to respective cup members to cause them to rotate therewith, stop means on the cover engageable by the members to limit rotation of the members, arms, and shafts, a spring means within said cavity acting on the members to urge them to rotate in opposite directions and hold the members against the stop means, an operating arm pivoted to swing on the axis of the shafts, and means for connecting the arm to one of the shafts.

11. In a door closer, the combination of a chamber having an open upper end, a partition within the chamber defining a cylinder having its lower end closed and its upper end open, connections between the cylinder adjacent its closed end and the chamber, one connection containing an inlet check valve and the other an outlet control valve, a piston within the cylinder having an internally threaded extension provided with diametrical external projections, a bearing within the chamber at its lower end below the cylinder, an inner shaft extending through the chamber, cylinder, and piston into the bearing, the shaft having a threaded section screwed into the piston extension, an outer shaft concentric with the inner shaft and having an extension overlappin the piston extension and having longitudinal slots receiving said projections, a cover for the chamber having a bearing from the outer shaft, a pair of members encircling the shafts and connected to respective shafts to rotate therewith, stop means on the cover engageable with the members to limit their rotation, spring means between and acting on the members to urge them to rotate in opposite directions and to hold them against the stop means, an operating arm pivoted to swing on the axis of the shafts, means for connecting the arm to one of the members.

12. In a door closer, the combination of a cylinder having a closed end, an inlet into and an outlet from the cylinder adjacent its closed end, the inlet containing an inlet check valve and the outlet containing a control valve, a piston within the cylinder having an internally threaded axial extension, a pair of concentric rotatable shafts, the inner shaft having a threaded section screwed into the piston extension, means for connecting the outer shaft and the piston for rotary movement in unison, while permitting their relative longitudinal movement, stop means, members connected to the respective shafts to rotate therewith and engageable with the stop means to limit rotation of the shafts, spring means connected to the shafts and urging them to rotate in opposite directions and hold their member in engagement with the stop means,

an operating arm pivoted to swing on the axis 25 of the shafts, and means for connecting the arm to one of the shafts.

13. In a door closer, the combination of a cylinder having a closed end, an inlet into and an outlet from the cylinder adjacent its closed end, the inlet containing an inlet check valve and the outlet containing a control valve, a piston within the cylinder havin a threaded portion extending axially of the piston, a pair of concentric rotatable shafts, one of the shafts having a threaded section engaging the threaded portion of the piston, means connecting the other shaft and the piston for rotary movement in unison, while permitting their relative longitudinal movement, stop means, members connected to the respective shafts to rotate therewith and engageable with the stop means to limit rotation of each shaft in one direction, spring means connected to the shafts and urging them to rotate in opposite directions and hold their members in engagement with the stop means, an operating arm pivoted to swing on the axis of the shafts, and means for connecting the arm to one of the shafts.

MAX KALTHOFF.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,249,190 Quentin Dec. 4, 1917 1,840,558 Bernhard Jan. 12, 1932 

